Indonesia's recent purchase of several older-design Sukhoi Su-27 Flanker combat aircraft from Russia highlights a crucial lesson of weapons development and international arms sales -- technical superiority is relative, not absolute. You don't need state-of-the-art weapons if your potential enemies are only equipped with older ones. Just making sure you have a sufficient quantitative and qualitative edge on them will do just as well.

Indonesia is the world's fourth most populous nation after China, India and the United States. It is a vast archipelago of 17,500 islands, 6,000 of them inhabited. It faces no serious military threats from any of its immediate neighbors. It therefore does not need a modern, state-of-the-art air force that would be more than a match for anything the United States, Russia or China could throw against it.

Indonesia's prime concern is to maintain conventional military superiority over possible internal secession movements, extreme Islamist guerrillas or other home-grown threats. To deal with these issues, a modern air force is essential. But it doesn't have to be a large or state-of-the-art one. The Sukhoi Su-27 Flanker B, which first entered operational service with the Soviet air force a quarter-century ago, is still good enough to do the job.

As we have previously noted, Russia certainly concentrated many of its best T-90 main battle tanks to ensure the success of its five-day mini-blitzkrieg campaign against the former Soviet republic of Georgia in the Caucasus last August. But the bulk of Russia's MBT force comprised older tank models. The Georgian army had been equipped lavishly with high-tech American equipment. But its new weapons had been anticipated for use in counterinsurgency operations or against forces operating from the Russian-backed enclaves of South Ossetia and Abkhazia. Neither the U.S. government of President George W. Bush nor the Georgian government of President Mikheil Saakashvili had anticipated that Russia would simply send its heavy ground forces against Georgia in an old-fashioned, full-bodied invasion operation. But when that happened, a lot of older but still very usable Russian military equipment worked just fine.

It is becoming increasingly fashionable to argue that major powers like the United States do not need large, heavy and "balanced" ground forces anymore because the wars of the 21st century are going to be fought by non-state forces or primarily as guerrilla wars and as counterinsurgency operations. This view has become fashionable among American pundits since the long-running Sunni Muslim insurgency in central Iraq caught them by surprise in 2003-6.

However, this sweeping, simplistic claim has often been made before, and it has been proven wrong before. Although the Vietnamese guerrillas stymied first French and then U.S. military forces in Vietnam in the 1950s and 1960s, the decisive victories in both conflicts were won by conventional military forces.

The Viet Minh used forces equipped with heavy artillery to conquer the French outpost of Dien Bien Phu in 1954, and it was the North Vietnamese army that finally conquered South Vietnam in 1975 by rolling into Saigon with an overwhelming force of Soviet-supplied main battle tanks. That force would have been no match for the U.S. Army and its NATO allies in Central Europe, but it was enough to get the job done against the embattled Armed Forces of the Republic of Vietnam.

In war, victorious forces don't have to be perfect, but they do usually have to be better equipped than the combat forces they're up against.

(Part 2: Lessons from Iraq's forgotten victory)